Process and means for automatically matching at least two substantially cylindrical surfaces, engaging each other, particularly for mechanical emboss engraving, and engraved plates obtained with such process and means

ABSTRACT

A process and machine for automatically matching at least two substantially cylindrical surfaces for engaging each other, particularly for the purpose of mechanical embossment engraving. The ranges of freedom of a conventional machine are mechanized and subjected to an electronic control, providing a hardware structure driven by software. The software controls the starting, repetitive and final steps, automatically complying with spacing and timing. The operator&#39;s action is needed only for loading of the roll to be worked, setting the inherent knurling tool, setting the starting positioning, and starting the cycle, as well as, for removing the unfinished roll for the corrosion steps and of course for final unloading.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a process and apparatus forautomatically matching and engaging two substantially cylindricalsurfaces. At least one of the cylindrical surfaces is a knurling toolfor mechanical emboss engraving, particularly of rolls. The embossedrolls are used for embossing sheet materials and the like. Furthermorethe present invention relates also to the mechanical engraved platesobtained with such process and means Chemical corrosion can be used tocomplete the engraving process.

2. Prior Art

At the present state of the art, processes and means for matching twosurfaces to engage each other, particularly for mechanical embossengraving, are both time consuming and repetitive. Most often theseprocesses and means are manual due to the difficulties encountered inautomating them. These processes and means, being difficult to obtain,are provided only on relatively expensive machines operated by highlyskilled and specialized operators. The process uses a long machine cycleand requires the operator's constant presence and checking. The engravedproducts obtained with such process and means are very expensive andhave poor precision because of inconsistency of the operator's abilityand skill. Operation of the manual machine was limited to regular worktime because night shifts or expensive overtime was not desirable.Recourse to overtime work was inevitable when preparation time was soextensive that delivery time was also extended. More than one machinecould not be used to make the same piece. The stressful character ofperforming this work, combined with the responsibility connectedtherewith was very high because an almost finished roll could be damagedby a small lack of attention, and it was usually not possible to remedythe defect in time. A real and present danger was the need for theoperators to put their hands in very risky places.

In particular, an operator has the task to move the active surface of aknurling embossing tool, under pressure to mate with a generallycylindrical passive surface to be mechanically engraved or embossed.Generally the size ratio, between one or more tools and the roll to beengraved is from 2 to 10 with reference to diameter and from 10 to 1000referring to the whole roll length. Thus, in the course of longitudinalworking the roll, the knurling tool must be displaced at leastlongitudinally, a corresponding number of times. Each time the knurlingtool is moved it must be checked against the correct matching referenceto suitable markers. However, when the longitudinal repetition pitch ofthe design exceeds 4-5 cm, a substantially double knurling tool lengthis needed. When the necessary pressure for an embossing processsubstantially exceeds the power of the machine, the barrel-like shape ofthe knurling tool is increased. The same knurling tool is used byfractionally varying the axes of inclination of same knurling tool 4-5cm each time. For this reason the machine is provided with a third rangeof freedom, a Z axis, in order that this parameter may be adjusted. Ifthe repetitivity of the design to be embossed has a worm trend, anangular excursion of the knurling tool with respect to the roll to beworked was made manually. The knurling tool was moved along itslongitudinal axis. Thus, the operations to be made manually, in eachworking step, are from a minimum of two to a maximum of four. Thisrequirement was a further obstacle to automation since, each designrequires a different working cycle, which must be precisely compliedwith for a good product.

SUMMARY OF THE INVENTION

The invention, as claimed, is intended to remedy these drawbacks. Theinventor has conceived a process and means for automatically matching atleast two engagement surfaces, that of knurling tool and that of roll tobe engraved. This invention is particularly useful for mechanical embossengraving, whereby the ranges of freedom of the manually operable toolmachine are mechanized and subjected to electronic control. A hardwarestructure is provided to be automatically driven by the software. Thesoftware can read the design to be engraved, and control the starting,repetitive and final steps, complying with locations and times. Theoperator's action is needed only for loading both the roll to be workedand the knurling tool, for setting the positioning and starting thecycle, and then for removal of the unfinished roll for the corrosionsteps and for the final unloading.

In particular, the machine substantially has a conventional structure,such as of a lathe-like machine, wherein the tool comprises a knurlingtool. The machine has four ranges of freedom including that ofsubstantially radial, which, is subjected to a press for radialapproaching. In accordance with the present invention, the roll to beworked is moved by the action of a D.C. motor. The motor is controlledby an encoder. The signals of the encoder may be referred to as correctpresent settings of roll to be worked, even relatively to position, atleast longitudinal, of the knurling tool.

The four ranges of freedom, as well as the fastening condition, whichoccurs without turning of the knurling tool, are characterized asfollows. Longitudinal movement of the carriage, whereon the knurlingtool carrier device is installed, is achieved by a conventional screwand/or bar of the machine tool. The conventional screw and/or bar arerotated by a separate d.c. motor and the position of the carriage withrespect to the roll is controlled by an encoder. Limit switches may beinstalled at the ends of the roll to be worked.

The second range of freedom comprises a substantially radial, and asubstantially vertical, movement of approaching and removal of theknurling tool to and from the roll to be worked. Such range of freedomincludes a base place to be determined once manually. The base place isset by adjusting a screw, to determine the position chiefly centripetalto the angular excursion which is provided by a first class leversuspension. The power is provided by a pneumatic or hydrauliccylinder-piston unit, subjected to a hydraulic station, and is adaptedto be driven by an electrovalve, and controlled by signals coming from acomputerized electronic system. This second range of freedom is limitedby a limit switch.

The third range of freedom comprises rotation of the knurling toolaround its axis. The knurling tool which is substantially idle, isinduced by the roll to be worked, when the knurling tool engages it. Theknurling tool although rotated on its Y axis when encountering the rollto be worked can be braked as needed by a brake device or a fasteningdevice in the time period between detaching and reapproaching.

The fourth range of freedom is comprised by angular movement of theknurling tool about a fixed fulcrum. Rolling of generatrixs of tangencymay take place by a driver including a second class lever. The driver ispowered by a screw loading a spring and has as resistance asubstantially bridge-like support, carrying the knurling tool. Verticalpositioning of the knurling tool is provided by extending a pistonwithin a fluidynamic cylinder, thereby providing operating pressure.This range of freedom is used only when the pitch or ratio, of thedesign to be engraved, is greater than 4-5 cm, and the correspondinglength of the knurling tool is greater than 8 cm, with a barrel-likeshape. Possible use of this fourth range of freedom is needed duringmovements regarding the third range of freedom.

Control of these four ranges of freedom conventionally was mademanually, at least on driving and/or starting and/or adjusting and/orstopping. The present invention solves these a specific problems. Inparticular, regarding the first movement: the lead screw is driven by apermanent magnet motor which is powered by a d.c. cable. A telereverser,not shown, acts on the magnet and is placed within the electric panel.The lead screw is coupled in axial relationship with an encoder whoseinput and output terminals are connected to an electric and electronicpanel, to be described. The range of movement of the carriage is limitedby two limit switches. The limit switches are electrically connected, bywires, to the electric panel.

Referring now to the second movement, instead of a manual driver device,which was removed, an alternative, fluidynamic motor is used. Thefluidynamic motor is fed by a hydraulic station. The electrovalve systemand circuit associated thereto and controlling such movement haveduplicate members and controls. The duplicate members and controls allowtwo different intensities of presssure. The pressure is adjustable andis lower at the beginning and for a certain time, set by a timer. Then afull pressure is used. The full pressure is adjustable too, set once andholds the pressure for a period of time.

The hydraulic station also drives another device, to be describedhereafter, substantially with reference to third movement.

The third movement includes an asynchronous three-phase motor with apermanent magnet d.c. motor. The same motor is the indirect drive of aroll gripping chuck. Such driving is provided through a belttransmission and gears. The encoder, associated with this movement formonitoring the real movement of the roll to be worked, is engaged by thecylindrical surface of the leading disc. The leading disc includes adog-like driving means which has substantially zero clearance, both withrespect to the hub of the roll to be worked and thus with the roll, aswell as with respect to the leading disc.

This third movement is of decisive importance, since it providesrotation of the knurling tool. The knurling tool pivots are idly mountedon its supports, in a conventional manner. The unbraked knurling tool isinduced to rotate by the rotation of the roll.

As soon as a complementary relief is formed on the roll, a propermeshing is established with the knurling tool. The proper meshingeliminates the need for a reference mark on drivers and transmissionmembers upstream of the encoder and engaged by the driver disc and onthe disc itself.

To re-establish meshing between the knurling tool and the roll 4, aftereach longitudinal movement of the knurling tool,

1) when the two members providing the coupling, have to reencounter eachother in the same reciprocal angular position as when linearrepetitivity is required, both in case that the reencounter happens tobe at reciprocal different angular positions, dictated by longitudinalpitch P and by angular pitch p of the drawing, or

2) when the position that the knurling tool is providing (design withworm or angular repetitivity).

In the first case a substantial absence of movement of the roll to beworked, corresponds with the absolute immobility of knurling tool.According to a preferred embodiment of the present invention, the endpivots of the knurling tool, are longer than conventional ones. The endpivots extend outward from the supports and are engaged by a pair ofbrake shoes. The brake shoes are driven by alternative fluidynamicmotors controlled by electrovalves and fed by the same hydraulic stationwhich provides pressure for the second movement. In the second case, theabsolute immobility of the knurling tool is obtained in the same manner.The knurling tool is made to correspond with an angular movement whichis controlled by an encoder, while, during engaging and disengagingthere is a small gap of idleness, of the roll. An almost spontaneoussmall adjusting of the angular position favors engaging and disengagingof the projections. Following an arcuated stroke, the knurling tool goesfreely to and from the tangency or engagement condition.

Because semiautomatic operation of the system occurs in an operator'sabsence, an automatic lubricating system is needed. The system canoperate up to 120 hours unattended and the automatic lubricating systemlubricates the pivots of the knurling tool. Different lubricatingmethods are used. Lubrication is accomplished by soaking or by timedforced injection.

Referring now to the fourth movement, it includes a screw driving akinematic device. The kinematic device comprises a mechanized reactionspring which provides the screw with a member which is driven by acomplementary member. A permanent magnet D.C. motor with power suppliedthrough a wire drives the complementary member. An encoder powered by acorresponding cable is axially coupled to the screw. A pair of angularlimit switches, connected with cables, are also placed on the screw andwherein the screw pitch is such to maintain the excursion within anangle less than 360°.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to explain the features of the present invention, reference ismade to the accompanying drawings which show one possible embodimentthereof in schematic manner and merely by way of explanation.

FIG. 1 is a schematic perspective view of a machine, in accordance withthe present invention, wherein the substantially conventional parts, areshown in phantom lines. The parts, according to the present invention,are shown in solid lines and in a relatively simplified and/or symbolicfashion. The input and output signals and power circuit are allconnected with an electric and electronic panel contained in a separateshelf body.

FIG. 2 is a flow chart, of the electric and electronic panel.

FIG. 3 is a detailed perspective view, of the most important parts ofthe operating machine, in the attitude wherein a roll is being engraved.A number of same parts are sectioned or broken to show other partsconcealed thereby.

FIG. 4 is a substantially symbolic, front view of caricatured positions.The knurling tool is shown with an exaggerated barrel-like shape withregard to a roll being engraved. On the left side of FIG. 4 are linesbroken in differentiated fashion. The projection of the three successivepositions and their effects are provided by the knurling tool, simplyrolling, in tangency contact, on the roll. On the right side of FIG. 4the knurling tool is shown already fed by more angular and longitudinalpitches, and is in the final rolling step. FIG. 4 shows both thebarrel-like shape which, in practice, is included in a range between z1and z4, and 0,6 mm, of radius difference and rolling, as well aslongitudinal and angular feeding.

FIG. 5 is a front view of the control console.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the figures of the drawings, a machine for mechanicalengraving of rolls includes, conventionally, a lathe-like structure,including a frame 9. The frame 9 has guides 9', two boxes 9", a head 90having a gripping chuck 91, the gripping chuck 91 is driven by a motor5, a pair of steady rests or supports 92, 92' a carriage 93 having anapron 94 mounted to the steady rests 92 and 92' and a screw 95 comprisesthe operative engraving unit. The operative engraving unit also includesa knurling tool 3 having four ranges of freedom, including asubstantially radial movement for approaching, which is caused by theaction of a press 2.

According to the present invention, a D.C. motor drives the grippingchuck or faceplate 91 to which the roll 4, to be worked is attached. Theroll 4 turns around its axis. The d.c. motor 5 receives electrical powerby means of cable 5' from the electric panel 7 and is controlled by anencoder 50. Signals from the encoder 50 are received through one or morewires 50' and these signals may be referred as present correct positionsof the roll 4 being worked. The present correct positions are also usedto position, at least longitudinal the position of knurling tool 3.

The four conventional ranges of freedom and, in accordance with thepresent invention, the braking or unbraking of the knurling ischaracterized as follows. Longitudinal movement of the carriage 93, onwhich the knurling tool unit 1 is mounted, is driven by a conventionalscrew 95 of a machine tool. However, knurling tool unit 1 isdisassociated from the rest of the tool machine and driven by motor 6,receiving electrical power by means d.c. cable 61", and its position isdetermined by an encoder 6'. The signals generated by the encoder 6',referred to as correct present postion, of knurling tool 3 with respectto roll 4 are transmitted through one or more wires 61'. Limit switches60, 60' connected to the electric panel through cables 60", 60"' may beplaced at the ends 4', 4" of roll 4 to be worked.

The second range of freedom, of knurling tool 3, comprises asubstantially radial and substantially vertical movement, forapproaching and displacing it away from the roll 4 being worked. Suchrange of freedom includes a base position, to be determined manually,only once. The base position is set by adjusting a screw 2' of press 2,to determine the utmost centripetal position, of angular extension. Thepress 2 is driven by a first class lever suspension, as is known whichis powered by a fluidynamic or hydraulic cylinder-piston unit 20according to the present invention. A fluidynamic or hydrauliccylinder-piston unit 20 is connected to a hydraulic station 21, and iscontrolled through a pair of electrovalves 22, 22'. The pair ofelectrovalves 22, 22' are in turn controlled by input signals comingthrough wires 22", 22'" from the electronic computerized circuit 7. Eventhis range of freedom is limited by a limit switch 123, connected to theelectronic computerized circuit 7 by wire 123'.

The third range of freedom includes rotation of the knurling tool 3 onits projecting hubs 3', 3" about its axis. The knurling tool 3 issubstantially idle and rotation is induced by the roll 4. (This is namedthe Y axis.) The knurling tool 3 engages the roll 4 and therefore theywill rotate at the same time. A temporary braking or fastening device 8is operated to cover the time gap between removal and re-engagement ofthe knurling tool 3. These brakings allow compliance with the secondrange of freedom, which are consequent to each positioning, according tothe first range of freedom.

The fourth range of freedom is comprised by angular excursion (about theZ axis) of axis defined by the hubs 3', 3" of knurling tool, about afixed fulcrum 30. Generatrixs (03) Z1, Z2, Z3, Z4, of tangency, may takeplace by driving a system, as is known. The system includes a secondclass lever, which has, as power, a screw 30' loading a spring 30" andas resistance a substantially bridge-like support 31, carrying knurlingtool 3. Vertical positioning, of knurling tool 3 is provided byextension of piston 20', within the fluidynamic cylinder 20 whichprovides the operating pressure. This range of freedom, is used onlywhen the pitch or ratio, of the design to be engraved, is greater than4-5 cm, with a corresponding length of knurling tool 3 greater than 8cm, and having a barrel-like shape 03. This range of freedom maypossibly be needed during movements regarding the third range offreedom. Conventionally these ranges of freedom, were controlledmanually, at least for driving and/or starting and/or adjusting and/orstopping. According lo the present invention, suitable means areprovided, already described in part, to solve the specific problems.

In particular, regarding the first movement: the lead screw 95 is drivenby a permanent magnet motor 6. The permanent magnet motor 6 is poweredby a D.C. cable 61". The permanent magnet motor 6 is subjected to atele-reverser, not shown, placed within electric panel 7. The lead screw95 is coupled in an axial relationship with an encoder 6' whose inputand output terminal 1', is connected to the electric and electronicpanel 7. The excursion range of carriage 93 is limited by two limitswitches 60, 60', also electrically connected, by wires 60" and 60"', tothe electric panel 7.

Referring now to second movement, instead of a manual device driver, notshown, which has been removed, an alternative fluidynamic motor 20, fedby a hydraulic station 21 is used. A pair of electrovalves 22, 22" haveelectrical wires 22", 22'", connected thereto for controlling the secondmovement. A duplicate of members, not shown, includes drivers 23, 23',controlled by electrovalve 24, connected by wire 24' to the electricpanel 7 whereby the approaching pressure applied to fluidynamic motor 20is provided with two different intensities: adjustably lower at thebeginning and upon a certain time set on a timer 23" connected to theelectric panel 7 by wire 23"', a full pressure, which is adjustable too,once and for a certain time. On the other hand, the hydraulic station 21drives also another device, to be described hereafter, substantiallywith reference to the third movement.

The third movement, includes the substitution of a conventionalasynchronous three-phase motor, not shown, with a permanent magnet d.c.motor 5 which indirectly drives a roll gripping chuck 91. The driving ofthe roll is provided through a belt transmission 50" and some gears, notshown. An encoder 50, associated with this movement, monitors the realmovements of roll 4 that is to be worked. The roll 4 is engaged bycylindrical surface 91', of gripping chuck 91. The gripping chuck 91includes a dog-like driver 91", substantially without clearance, bothwith respect to the hub 4"', of roll 4, to be worked and thus of thesame roll, and with regard to gripping chuck 91. This third movement isvery important, not only in itself, but since it determines the rotationof knurling tool 3. The rotation of the knurling tool is provided withhubs 3', 3" idly mounted on respective supports 33', 33", in aconventional manner. Such movement is induced, in fact it is provided bythe engagement of the knurling tool 3, which may be defined as toothedwith the roll 4. As soon as a complementary relief is formed on the roll4, a proper meshing is established, which obviates the provision of areference mark on driver and transmission member, upstream of encoder50, engaged by gripping chuck 91 and on the disc itself. In order tore-establish this meshing, between knurling tool 3 and roll 4, aftereach, longitudinal movement of knurling tool 3, two cases can arise. Thefirst case is when the two members 3 and 4, providing the coupling, haveto reencounter in the same reciprocal angular position as when embossinga design having linear repetitivity. The second case is that thereencounter happens to be on reciprocal different angular positions,dictated by longitudinal pitch P and by angular pitch p of a design withworm or angular repetitivity (FIG. 4). In the first case, a substantialabsence of movement of roll 4 to be worked, corresponds to absoluteimmobility of knurling tool 3.

According to a preferred embodiment of the present invention, the hubs3', 3" of knurling tool 3, are longer than conventional ones. The hubs3', 3" extend outward from supports 33', 33", in order to be engaged bya pair of brake shoes 34, 34'. The brake shoes 34, 34' are driven byfluidynamic motors 35, controlled by electrovalves 22, 23 and fed by thesame hydraulic station 21, providing the pressure for the secondmovement. In the second case, the absolute immobility of knurling tool3, obtained in the same manner, is made so that a movement of the rollcorresponding with an angular movement p, controlled by the encoder 50can be made. During engaging and disengaging of the knurling tool 3 withthe roll 4 there is a small gap of idleness, of roll 4. An almostspontaneous small adjusting of the angular position of the knurling tool3 is made, such to favor the meshing engagement and disengagement ofprojections while, after an arcuated stroke, the knurling tool 3 goes toand from the tangency or engagement condition.

As a result of semiautomatic operation of the system in operator'sabsence even for very long periods up to 120 hours and more, anautomatic lubricating system 13 is needed. The automatic lubricatingsystem 3 provides lubricant to the hubs 3' and 3", of knurling tool 3.Such lubricating system is automatic and has varied lubrication methods,i.e. by soaking, and with timed forced injections.

Referring now to the fourth movement which, conventionally, is providedby the screw 30', driving a kinematic device 31. The kinematic device 31includes a reaction spring 30". The screw 30' was provided with a member36, driven by a geared transmission. The geared transmission is drivenby a complementary member 36' driven by a permanent magnet d.c. motor36". Permanent magnet D.C. motor 36" has power supplied to it throughwire 36"'. Encoder 37 is connected to electric panel 7 by cable 37' andis axially coupled to the screw 30'. A pair of angular limit switch 38,38', connected to electrical panel by cables 38" and 38"'are also placedon the screw 30'. The screw pitch is such to maintain the excursionwithin an angle less than 360°.

From what has been described heretofore the system operation should beevident, however a rough explanation will be given also with referenceto two embodiments. More particularly example I shows a roll including adesign of the kind not employing all the resources of the system.Whereas example II, expressly referring to FIG. 4, thoroughly uses allthe system resources. In an appendix of example II the program isroughly described which is suitably provided and that, opportunelysimplified may be used to program also example I.

EXAMPLE I

Having to engrave a roll 4, for special paper embossing, sized 500 mm indiameter and 4500 mm long; the blank roll 4 was duly provided and themachine was prepared, in a substantially conventional way. Roll 4 waslathed, stablized and ground. Keying means were prepared on the roll forkeying to the driving dog 91". Spacer rings and end bearing 492, 492',were added to adequately support the diameter of the roll 4 in thecylindrical supports 92, 92'.

Referring now to the machine arrangement, carriage 93, carrying theengraving operative unit 1, is conventionally placed at the end 4' ofroll 4. On the same unit, is mounted the knurling tool 3, in aConventional manner. However, instead of a conventional assembly inorder to support the knurling tool 3 a suitable bracket, not shown, maybe put on or removed. Braking shoes 34, are provided, which aretemporarily released and removed, in a way to be explained later on.Again, in conventional manner, the position of knurling tool 3 is set,the mounting is checked and corrected, with a suitable adjusting screw.At this stage, according to the present invention, the hydraulic station21, is started. The hydraulic station provides a lower pressure, atleast in cylinder 20, at least to reach about 3 atmospheres. Thus roll4, is caused to rotate and pressure is gradually increased, to reachabout 10, 12 atmospheres. When the operator realizes that everything iscorrect, the program is started for automatic prosecution of engraving,along the whole roll 4 or along part of it. Substantially no furtheroperator's intervention is needed except for the final unloading of theroll or possibly an intermediate stage to provide a corrosion step. Theprogram for a determined roll 4 is programmed only once and may be usedrepeatedly to provide a single engraving from end to end. Having torepeat the engraving, intervention is required by the operator, toreturn the carriage 93, including the engraving operative unit 1, to theend 4' of roll 4, substantially in starting condition, checking andadjusting the matching between the knurling tool 3 and the alreadyengraved track, as well as with program repetition.

EXAMPLE 11

Having to engrave a roll 4, for paper-cloth embossing, sized 450 mm indiameter and 2700 mm long, the blank was duly provided, as described inexample 1. Reference is now made to the drawing to be engraved. Inaccordance with example I, the repetition of the drawing was to be madein a mere linear fashion. Only one placing of carriage 93 is needed fora mere linear repetition that involves the use of only two axes X and Y.Whereas, in the drawing of this example II, the knurling tool 3 has alength, dictated by drawing pitch. Control of the Z axis is necessaryfor using the knurling tool 3 along the whole length. Moreover, thenature of the drawing dictates that, against each longitudinal placingof knurling tool, an angular excursion on the Y axis is provided. Themachine arrangement, repeats that of example I, up to the state whereinroll 4 is caused to rotate and pressure is gradually increased, to reachabout 10, 12 atmospheres. It is to be realized that the operatorverifies through manual excursion of the whole Z axis field fromposition 1 to position 4 of FIG. 4, that everything is correct. However,before starting the program for automatic prosecution of engraving, incontrast with example I, the knurling tool 3 is placed in position 1 ofFIG. 4. Thus, as in example I, the program which obviously is differenttherefrom, for execution and repetition of cycle is started. The programwill be such to control the X, Y, Z axes, wherein control of Y axisinvolves the additional function of roll repositioning. Rollrepositioning requires an angular excursion corresponding with drawing,along the whole length of roll 4 or on one part thereof. No furtherintervention is required by the operator, exception made for the finalunloading of roll or possibly an intermediate stage to provide acorrosion step. As in example I, the program, for a determined roll 4,is programmed only once and may be repeatedly used to provide a singleengraving from end to end. Repeating the engraving requires anintervention of the operator to return the carriage 93 with theengraving operative unit 1 to the end 4' of roll 4 (substantially, thestarting condition). Other steps include checking and adjusting thematching between the knurling tool 3 and the already engraved track, aswell as with program repetition.

For automatic running of embossing programs, a numerical control isused. FIG. 2 shows a numerical control substantially comprising acentral unit 70, including a microprocessor 71, EPROM memories 72, RAMmemories 72', mathematic co-processor 73, serial interface 74, ananalogic output 75, an input/output port 76, and a digital output 76'.The central unit 70 is connected with nine modules: an input controlmodule 77, an output control module 77', a console module 77", an Xpositioning module 78, an X-counting module 178, a Y positioning module78', a Y-counting module 178', a Z positioning module 78", a Z countingmodule 178", as well as power supply 79. The numerical control includes,in 101 the machine input, in 102x, 102y, 112z the on/off and reference,in 103 the miscellaneous output and in 104x, 104y, 104z the input forpositional transducer encoder type. Between the on/off 102x, 102y, 102zand respective input 104x, 104y, 104z, for position transducers 6', 50,37, are connected: motor 6, 5, 36", driver, not shown, tachometer, andencoder 6', 50 and 37. Between the on/off 102x, 102y, 102z andrespective input 104x, 104y 104z for positional transducer 6', 50, 37,motors 6, 5, 36" driver, tachometer, and encoders 6', 50 and 37, areprovided.

In accordance with a preferred embodiment of the present invention,microprocessor 71 is of Z 80 or 6502 or cdp 1802 type, the EPROMmemories 72 are of the 27512 type or of the 27256 type. Also accordingto the present invention the RAM memories 72' are static, of 6264 type,with back battery, the mathematics co-processor 73, is of AMD 9511 type,and serial interface 74 is of RS232 C type.

Numerical control has substantially the following characteristics. Itcontrols three axes, displacement range is +/- 9999,99 mm, accelerationsare programmable, circular interpolation on plane, linear interpolationon all axes, programming support with parametric instructions, referencepoint machine cycle. Programming is absolute and/or incremental and withhost computer, DNC mode and teach. Programmable functions are asfollows: miscellaneous functions (M), preparatory functions (G), feedfunction (F) for axes, spindle function (S), nesting subroutine, nestingloop functions and reference point translation thereof; completesecurity diagnostic continuous checking; auto-test with variablepolling; machine transducer with continuous diagnostic; manuallyoperable in two ways with continuous and adjustable of all the axes andby programmable single steps. The interface includes 32 testable inputs,32 24V, 100 mA, outputs +24V, 1,2A, output; output stages are of opencollector type with TR BD677 type or MJ 3001 type; working is tested byexternal gauges (reading in BCD code). Referring now to memories: memory(72) is of 64 Kbyte, expandable up to 256 Kbyte and RAM memory (72') isof 18 Kbyte expandable up to 50 Kbyte.

The control console in FIG. 5 comprises: a 270 LED display, to displaythe digits of x, y, z axes; of program block numbers, of theinstructions given; display (271) by shifting; Keyboard (272) with keys0 to 9, keys + and - as well as keys for switching the function$elector, as well as the delete key and keys start and stop; feed rateoverride (273) from 10% to 100%; mode selector (274) of the operationmodes with the following positions:

a) manual;

b) loading working program;

c) checking or correction of working program;

d) position auto-teaching;

e) parameter loading;

f) automatic;

g) semautomatic; (single block)

h) absolute JOG;

i) incremental JOG;

Programs drafted taking into account these particulars.

APPENDIX

The program for engraving of roll 4, with the drawing of example IIshown in FIG. 4 is the following:

1)M24, 2)@t1; 3)M21; 4)@t2; 5)M23; 6)G91; 7)Zz1-z4; 8)@t3, 9)M83;10)@t4; 11)M22; 12)@t5; 13)M82; 14)@t6; 15)M81; 16)M84; 17)G91;18)Zz4-z1; 19)G91; 20)XP; 21)G62; 22)M25; 23)Yp; 24)M85; 25)@t7;26)JnP-1; 27)M99.

In such program M is a function and precisely: 21=unbraking of knurlingtool 3; 22=back rotation of roll 4; 23=forward rotation of roll 4;24=approaching of knurling tool 3 to roll 4; 25=p angular back rotation;81=braking of knurling tool 3; 82=stopping of roll 4; 83=stopping ofroll 4; 84=detaching of knurling tool 3; 85=stopping of roll; 99=end ofthe cycle. @ indicates the waiting time, of tn duration, wherein n isfrom 1 to 7. X indicates the movement of carriage 93 by a distance P. Yindicates the angular excursion of roll 4 by p angle. Z indicates theextent of angular excursion that knurling tool 3 has to make in the timet3+t4+t5. G indicates the axes commutation and a displacement of p, P,z1-z4, z4-z1 extent, and precisely: 62=on Y axis; 91, respectively, on Xaxis and on Z axis. J indicates the number of return to the programorigin 1) before passing to instructions M99.

I claim:
 1. A process for automatically matching at least twosubstantially cylindrical surfaces, for engaging each other, formechanical embossed engraving of a roll with an engraving tool, usingranges of freedom of a knurling tool, said process comprising starting,repetitive and final steps, including:mechanizing and subjecting saidranges of freedom to electronic control, by providing a hardwarestructure, available to materialize a software which, each time, canunderstand the design being engraved, and controlling the starting,repetitive and final steps, complying with spaces and times, in anautomatic mode, said step of controlling including the step of brakingof said knurling tool between each repetitive step to maintain a patternin said knurling tool aligned with a pattern engraved on said roll. 2.The process as claimed in claim 1, further comprising the stepsof:providing a roll to be worked; displacing said knurling tool, saidknurling tool having four ranges of freedom by means of a press toradially engage said roll; rotating said roll with a d.c. motor, saidd.c. motor being controlled by an encoder.
 3. The process as claimed inclaim 2, further comprising the steps of:controlling said four ranges offreedom and said braking to inhibit the rotation of said knurling toolwhen disengaged from said roll.
 4. The process as claimed in claim 3,wherein said step of controlling said four ranges of freedom includes astep of controlling a first range of freedom, said step of controlling afirst range of freedom comprising the steps of:longitudinally displacinga carriage, on which said knurling tool is installed said carriage beingdriven by a screw independently rotated by a D.C. motor; and controllingthe location of said carriage with respect to the roll in response tosignals generated by an encoder attached to said screw, and limitswitches installed at the ends of the roll to be worked limit thedisplacement of said carriage by said D.C. motor.
 5. The process asclaimed in claim 3, wherein said step of controlling said four rangesincludes the step of controlling a second range of freedom, said step ofcontrolling a second range of freedom comprises the steps of:approachingand removing of said knurling tool from said roll to be worked, in asubstantially radial, substantially vertical direction wherein saidsecond range of freedom includes a manually adjustment screw fordetermining a base place, to be determined once said process includesthe step of manually adjusting said manual adjustment screw to determinesaid base place for an angular excursion provided by a first class leversuspension, wherein said angular excursion is provided by a pneumatic orhydraulic cylinder-piston unit by an electrovalve controlled by signalscoming from a computerized electronic system, said second range offreedom being limited by a limit switch.
 6. The process as claimed inclaim 5 wherein said step of controlling a second range of freedomcomprises providing said hydraulic cylinder piston with two differentintensities; one of said two different intensities being lower at thebeginning and upon a certain time set on a timer, the second of said twodifferent intensities being a full pressure.
 7. The process as claimedin claim 3, wherein said step of controlling said four ranges of freedomfurther comprises the step of controlling a third range of freedom, saidstep of controlling said third range of freedom comprises the stepsof:inducing said knurling tool to rotate around its axis, by engagingsaid knurling tool with said roll to be worked and braking temporarilysaid knurling tool, in the time interval between said removing andapproaching of said knurling tool to said roll, in accordance with saidsecond range of freedom, associated with each longitudinal displacementof said carriage, in accordance with said first freedom range.
 8. Theprocess as claimed in claim 3, wherein said step of controlling fourranges of freedom includes controlling a third range of freedom, saidstep of controlling a third degree of freedom comprises the step ofcontrolling a permanent magnet d.c. motor for indirectly driving a rollgripping chuck, such indirect driving being provided through a belttransmission and at least two gears, an encoder associated to themovement of the roll gripping chuck, monitors the real movements of saidroll to be worked, said encoder being engaged by cylindrical surface, ofa leading disc of said roll gripping chuck, said roll gripping chuck,including a driving dog substantially without clearance, both withrespect to hub, of said roll, to be worked and thus with respect to saidleading disc.
 9. The process as claimed in claim 3, wherein said step ofcontrolling includes a step of controlling a fourth range of freedom,said step of controlling a fourth range of freedom comprises the step ofre-engaging said knurling tool with said roll at different angularreciprocal positions.
 10. The process as claimed in claim 3, whereinsaid fourth range of freedom is provided by a screw, driving a kinematicdevice, comprising a reaction spring, characterized in that said fourthrange of freeedom is mechanized, providing said screw with a memberdriven by a complementary member, driven by a permanent magnet d.c.motor, and wherein an encoder, is axially coupled to said screw, and apair of angular limit switches limit the rotation of said screw, whereinsaid limit switches maintain the excursion of said screw within an angleless than 360°.
 11. A machine for automatically matching at least twosubstantially cylindrical surfaces for engaging each other, formechanical emboss engraving of a roll, said machine comprising:astructure supporting said roll for rotation thereon about an axis ofrotation; means for rotating said roll about said axis of rotation; acarriage movably mounted to said structure, said carriage being movablein a direction parallel to said axis of rotation of said roll; aknurling tool rotatably mounted to a pair of supports, said pair ofsupports movably mounted to said carriage, said knurling tool rotatablein response to the rotation of said roll when said knurling tool is inengagement with said roll; means for pivotally moving said knurling toolinto engagement and out of engagement with said roll; means for axiallydisplacing said carriage a predetermined distance; a brake mounted to atleast one of said pair of support members selectively operable to engagesaid knurling tool and inhibit the rotation thereof; and means forelectronically controlling the operation of said machine includingcontrolling said means for pivotally moving said knurling tool, saidmeans for axially displacing said carriage, and said brake, said meansfor electronically controlling sequentially controlling the operation ofsaid machine through repeatable sequences progressively along said roll.12. A process for use on a machine tool for automatically matching aknurling tool mounted on a carriage, to a roll for mechanical embossmentof said roll with a pattern comprising the steps of:approaching andengaging said roll with said knurling tool having a predeterminedpattern for a first engraving engagement; unbraking said knurling toolto permit free rotation; activating a motor to rotate said roll in aforward direction of rotation so that said knurling tool knurls saidpredetermined pattern on said roll; stopping said roll after apredetermined angular revolution of said roll; braking said knurlingtool to prevent the rotation thereof; pivoting said knurling tool awayfrom said roll; displacing said carriage supporting said knurling toollinearly a predetermined distance with respect to said first engravingengagement of said knurling tool; rotationally indexing said roll tomatch the pattern on said knurling tool with the pattern engraved onsaid roll; and repeating said steps of approaching, unbraking,activating a motor stopping said roll, braking, detaching said knurlingtool, displacing said carriage supporting said knurling tool andindexing a predetermined number of times until a desired portion of theroll is engraved.